The motion dynamics of seats, in relation to a seat back which is possibly coupled to the seat squab, in dependence on the weight of the person using the seat, requires a suitably adjusted stressing force configuration for spring systems in order to urge the seat with the body weight into position, or for return to another position, for example into the vertical position. The problems involved with manual adjustment of the seat back inclination setting, usually by means of overcoming a spring stressing force, are often laborious and arduous. In the motor vehicle sector for example the seat inclination setting is often manipulated while a vehicle is travelling, which distracts the driver in terms of vehicle control and can therefore possibly cause an accident. In the case of spring stressing force systems which are coupled to the seat and the back, light or dainty, non-muscular persons can scarcely manipulate such a system because they cannot push the seat back backwards. Heavy muscular types on the other hand have the feeling of drifting off rearwardly when they wish to change the inclination of the seat back rearwardly.
Mechanical systems of adjusting mechanisms for adjusting or changing the position of the backs of seats, on a manual or motor basis, are sufficiently known and are state of the art. Such systems must always be individually adjusted in dependence on the individual stature of the user. An optimum individual and body-related seat back positioning and arresting can be implemented only with difficulty, if at all. If the seat back setting is not correct, the user, for example when using a motor vehicle seat, perceives the occurrence of back complaints and a certain tiredness only after a journey which has lasted a relatively long time. Even moving the back of the seat into a position which is only different but again not correct and securing it in that position provides at best an only temporary remedy because that corrected setting for the seat back is almost always not the right one.
The motion dynamics between the user of a seat with a seat back must always be in conformity temporarily and permanently and therefore must be resolved satisfactorily from the body-physiological point of view.